The present invention relates to a thread-feed device for textile machines having a stationary winder drum on which a thread fed from a stationary supply spool can be wound by means of a rotatable winder arm in order to form a supply of thread and the supply of thread formed can be withdrawn from above, and having a device for automatically controlling the rotary movement of the winder arm as a function of the length of the supply of thread formed.
Thread-feed devices of this type, which are known as forespooling devices, are known in many embodiments and are used both in knitting machines and in looms employing gripper and projectile type filling insertion devices. By the device for controlling the rotary movement of the winder arm a supply of thread sufficient for a filling insertion is always prepared on its winder drum. As soon as this supply of thread is withdrawn, thread is again placed on the winder drum by the winder arm.
For the requirements of the said looms in which the filling thread is introduced in positive fashion, the known forespooling devices serve their purpose since the insertion members which insert the filling thread in positive manner remove only just the required length of thread from the forespooling device so that said devices need merely store a sufficient length of thread.
The problem is entirely different in the case of jet looms in which the filling thread, as is known, is introduced in non-positive manner. In this case a thread-feed device must not only store a sufficient length of thread but, in addition, it must supply to the loom accurately measured lengths of thread at precisely determined times. Since the known forespooling devices do not satisfy these requirements, it has not been possible to use them heretofore on jet looms.
For jet looms there are known, on the one hand, thread-feed devices which have separate dimensioning and storage parts, the dimensioning part being formed by rotating rollers, reciprocating fingers, and the like, and the storage part by a pneumatic storage in which the thread is stored in the form of an elongated loop. On the other hand, there are known thread feed devices having a winder drum on which the filling thread is wound by a winder arm and is alternately blocked or released for the insertion of the filling thread by pins which periodically pass through the wall of the winder drum.
In the first-mentioned thread-feed devices, problems as to space arise, among other reasons, because of the fact that the length of storage increases with the weaving width. In the said second thread-feed device, precise synchronism must be present between filling insertion, movement of the winder arm, and movement of the pins.
These problems are multiplied as soon as different (for instance different colored) filling threads are to be inserted. In such case, as is known, a separate thread-feed device must be present for each color. In the case of the first-mentioned thread-feed devices, the space problems which in any event are present are, of course, increased. And the second said thread-feed devices can be used in this case only if the change of color takes place in a constant rhythm, in which case the speed of rotation of the individual units must be selected in proportion to this rhythm. As soon, however, as the color change is to be freely selectable, these thread-feed devices cannot be used because of the coupling between the movement of the winder arm and the pins, since as soon as and as long as a given filling thread is not required, the corresponding thread-feed device is stopped, but if the filling thread is required, then it must start up practically free of delay.
The closest prior art known to the inventor in connection with this application is U.S. Pat. No. 3,411,548, which is made a part of this application by way of reference.